1. Field of the Invention
The present invention relates to a reversible plow that can be pivotally shifted to selectively provide furrows that have the loosened earth deposited on either the right side or the left side of the center of the furrow. More particularly, the invention relates to a reversible plow that is vertically adjustable, relative to the plow draw beam, to permit variation of the angle that the plow structure makes relative to the ground, in order to selectively permit deep, medium deep, normal, and shallow plow depths.
2. Description of the Related Art
Various types of reversible plow structures have been developed over the years. Two examples of such structures are shown in U.S. Pat. No. 90,895, which issued Jun. 1, 1869, to W. H. Tyler, and in U.S. Pat. No. 291,503, which issued Jan. 4, 1884, to H. Gates. Each of the Tyler and Gates patents shows a reversible plow in which the reversible plow support structure is fixed in position relative to the draw beam, and the pivot axis of the plow remains fixed in a substantially horizontal position. Consequently, control of the depth of the plowing operation is achieved by upward or downward pressure applied to the plow handles by the operator.
Structures for permitting changing the angle of the plow structure relative to the plow draw beam are shown in U.S. Pat. No. 490,276, which issued Jan. 24, 1893, to D. B. English; U.S. Pat. No. 1,105,264, which issued Jul. 28, 1914, to D. H. Floyd; and U.S. Pat. No. 1,157,399, which issued Oct. 19, 1915, to W. A. Kimbell.
Although patents directed to plow structures have issued since the mid-19th century, it is believed that the combination of a reversible plow with plow support structure to permit selective vertical adjustment of the plow angle relative to the ground, is novel. Such a structural arrangement is highly advantageous in that the ability to vertically adjust the plow to change the angle at which the plow passes through the earth permits the plow orientation to be adapted to the extent of compaction and density of the soil, thereby providing a more versatile plow.
It is therefore an object of the present invention to overcome the shortcomings of the prior art structures and to provide an improved plow that provides in a unitary structure both reversible operation as well as vertical adjustment.